- March 11, 2011 – A 9.0 magnitude earthquake occurs off the East coast of Japan, triggering reactors 1, 2 and 3 at the Fukushima Daichi nuclear power plant to be shut down automatically. Reactors 4, 5 and 6 were already shut down prior to 3.11. Outside power is lost and diesel backup generators kick in to provide cooling in reactors 1-3. Shortly thereafter, a tsunami resulting from the earthquake strikes the plant, and the facility is inundated. The diesel generators are knocked out by the tsunami and backup batteries are instead used to power the cooling systems. Evacuation orders are issued for persons living within 3km of the plant. (NEA)
- March 12, 2011 – Backup batteries run out of power, making the cooling of reactors, 1, 2 and 3 all but impossible. The pressure within the reactor containment vessels increase sharply. Plant operators vent radioactive gasses out of the reactor housings in an attempt to decrease the pressure. The mandatory evacuation zone expands to all persons residing within 10km of the Fukushima Daichi nuclear power plant. A hydrogen explosion occurs in the reactor 1 building, causing spent nuclear fuel to be exposed to the atmosphere. The evacuation zone is expanded to 20km surrounding the plant. Sea water is pumped into reactor 1 to prevent further damage to its active nuclear fuel. (NEA)
- March 13, 2011 – Reactor 3 is vented to reduce building pressure and sea water is pumped into the reactor to prevent meltdown of its fuel. (NEA)
- March 14, 2011 – The reactor 3 building suffers a hydrogen explosion and its spent fuel is exposed. Water levels in reactors 1-3 decrease enough such that some of the fuel becomes exposed and fuel damage becomes imminent. Sea water injection begins in reactor 2. (NEA)
- March 15, 2011 – Venting of radioactive gas in reactor 2 begins but a hydrogen explosion occurs shortly thereafter. Reactor 4 is damaged by fire and by another explosion and its spent fuel is at risk of being exposed. The water levels in reactor 5 drop to below safe levels but emergency diesel generators are able to supply cooling and prevent any damage to its fuel. (NEA)
- March 16, 2011 – Evacuation within the 20km exclusion zone is completed. (NEA)
- March 16 – March 18, 2011 – Sea water continues to be injected into unites 1-3 to prevent further damage.
- March 19, 2011 – Elevated radiation levels reported in food and water from areas in proximity to the plant and elevated levels (though still under the acceptable limit) of radioactive Cesium and Iodine reported in water supplies further away from the disaster area. (NEA)
- April 12, 2011 – The Fukushima Daichi nuclear disaster is determined by many experts to be the most complicated incident of its kind to ever occur. (Fukushima.com)
- December 16, 2011 – Prime Minister Yoshihiko Noda announces that all reactors damaged by the Tohoku earthquake and tsunami are stable and in a state of cold shutdown. Complete decommissioning of the plant is expected to take 30-40 years. (NEA)
- December 26, 2011 – An investigation into the disaster concludes that lack of communication by the Japanese government and human error on the part of TEPCO (Tokyo Electric Power Company) employees exacerbated the severity of the disaster. (Fukushima.com)
- December 12, 2012 – TEPCO, the business operating the plant, admits its fault in the disaster for the first time.(Fukushima.com)
- Many thousands of people remain displaced by the disaster at the time of this webpage’s publishing. See the numbers here.
Video courtesy of Russia Today.
<https://youtu.be/kjx-JlwYtyE>
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Read about the effects of the Three Mile Island and Fukushima accidents.